PHX Sky Train Stage 1


One of the 10 busiest airports in the U.S., Phoenix Sky Harbor International Airport (PHX) transports nearly 40 million people annually and is the largest economic engine in the state of Arizona. Daily, PHX generates $79 million in economic impact and serves more than 1,200 aircraft and 100,000 passengers. For all its success, projected growth was standing in the way of airport operations and satisfied customers, and its existing landside transportation system was not equipped to handle the airport’s future ground transportation needs. In response, the PHX Sky Train® automated people mover (APM) system was born.

A vision of the City of Phoenix Aviation Department, the 1.92-mile-long PHX Sky Train features a transit-oriented design and links passengers between multiple ground transportation modes and the terminal. It smartly enabled airport growth by adding capacity to a severely constrained landside access network. Accomplished with a user-friendly system that improves connectivity to regional transit and roadways, the PHX Sky Train was placed into operation in 2013. One of the most forward thinking projects of our time, the PHX Sky Train has transformed ground transportation at PHX and created a world-class level of service and convenience for passengers.

What We Did

As the fixed-facilities designer of record for the PHX Sky Train project, Gannett Fleming designed a 1.92-mile-long elevated guideway that traverses 3,000 acres of landlocked airfields, terminals, and roadways. The project included three new elevated passenger stations and links the Phoenix region’s 44th Street Valley Metro light rail station with the airport’s economy parking area and the 88-gate Terminal 4.

Ingenuity and out-of-the-ordinary solutions were critical in addressing the logistically complex work. This unprecedented engineering feat required several first-ever design features, including the world’s first transit bridge over an active taxiway. This three-span, cast-in-place post-tensioned box girder bridge, with a 340-foot main span accommodates even a Boeing 747 aircraft. Going over the taxiway instead of under enabled designers to avoid a complex labyrinth of underground utilities and provided optimal alignment and a clean connection with Terminal 4. To accomplish this, Gannett Fleming worked with the Federal Aviation Administration (FAA) to develop acceptable design criteria for this overpass, the first FAA-approved design criteria ever developed for such an undertaking. The guideway crosses a variety of existing infrastructure, including the Union Pacific Railroad, which required precise coordination and design considerations. We additionally created an elevated spur line connection to a maintenance facility above an existing roadway and designed an elevated 240-foot radius horizontal curve to carry the guideway into the East Economy Parking Lot.

The CM-at-Risk model supported fast-track delivery of the project. It enabled early identification and mitigation of constructability issues and allowed for overlapping design and construction processes with 31 separate design packages. As a result, the construction schedule was condensed by two years and the project was delivered $10 million under budget.

Key Features

  • 1.92 miles of elevated guideway.
  • Electrically powered, driverless vehicles that operate 24 hours per day.
  • Three elevated passenger stations.
  • World’s first transit bridge over an active taxiway; 340-foot long, 90-foot high bridge accommodates Group V aircraft.
  • LEED Gold-Certified.

Awards & Recognition

  • Honor Award, 2014, American Council of Engineering Companies, Engineering Excellence Awards.
  • Clifford C. Sawyer Achievement Award, 2013, American Council of Engineering Companies Arizona, Engineering Excellence Awards.
  • Judges’ Award, 2013, American Council of Engineering Companies Arizona, Engineering Excellence Awards.
  • Outstanding Transit Innovation Award, 2013, Arizona Transit Association/Arizona Department of Transportation, Excellence Awards.
  • Exposing the Best in Concrete Award, 2013, Arizona Chapter of the American Concrete Institute, Exposing the Best in Concrete Awards.
  • Best Transportation Project, 2012, ENR Southwest magazine, Best of 2012 Awards.
  • Best Project in Safety, 2012, ENR Southwest magazine, Best of 2012 Awards.
  • Project of the Year Category 4-Escalator Modernization, 2012 and 2011, Elevator World magazine, Project of the Year Awards.
  • Innovative Transportation Solutions Award, 2010, WTS Metropolitan Phoenix Chapter, Recognition Awards.


  • Electrically powered, the PHX Sky Train reduces the airport’s daily vehicle count by 20,000, which reduces the airport’s greenhouse gas emissions by nearly 6,000 tons annually.
  • Three stations use 30 percent less power than established normal baselines.
  • Recycled materials, regional materials, low-water use facilities, energy optimization, low-emitting materials, and daylight illumination is expected to save the city more than $10 million in the first 20 years of operation.
  • The only LEED-certified public transportation campus in the world.
  • Alleviates roadway and curbside congestion for 100,000 passengers daily.
  • Provides access to 1,200 flights daily.
  • Exceeds projected ridership by 30 percent.
  • Enhances the airport’s long-term growth ability.
  • Saves the airport $10 million by year 2033 through LEED® efficiencies


City of Phoenix Aviation Department


Phoenix, Ariz.


Land Use Studies, Transportation Planning, Fixed-Facilities Engineering, Fixed-Facilities Design, Structural, Geotechnical, Vertical Transportation, Building Information Modeling, Security Systems Analysis, Contract and Project Management, Construction Monitoring

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